An SC-type optical connector has heretofore been developed for the purpose of building an optical communication network.
This SC-type optical connector has as a basic construction an alignment structure and a double fitting structure which are achieved by a zirconia ferrule which can be assembled even in the field, and this optical connector has been used mainly for the connection of a single-core cable of a silica-type single-mode optical fiber.
Recently, a mechanical splice-type connector which is an improvement of this SC-type optical connector has been developed.
This mechanical splice-type connector has been developed in order to achieve a high-density mounting at a lower cost while securing the compatibility with a conventional SC-type optical connector.
FIGS. 40 to 43 show a conventional mechanical splice-type connector.
The mechanical splice-type connector 1 shown here is disclosed in JP-A-11-160563 publication, and comprises a ferrule 3 containing a first optical fiber 2, a splice member 4 which holds the ferrule 3 and the first optical fiber 2 projecting from a rear end surface of the ferrule 3, and a connector housing 23 of a generally tubular shape covering an outer periphery of this splice member 4. A second optical fiber 20, made bare at a distal end portion of a coated optical fiber 19, is inserted into the splice member 4 through a rear end thereof, and the first optical fiber 2 and the second optical fiber 20 are butted within the splice member 4, thereby connecting the second optical fiber 20 to the first optical fiber 2.
The connector housing 23 comprises a front housing 17 covering the outer periphery of a front end portion of the splice member 4, and a rear housing 18 covering the outer periphery of a rear end portion of the splice member 4. The front housing 17 and the rear housing 18 are joined together by engaging retaining piece portions 18a (formed on an end portion of one of the housings) in engagement holes 17a formed in an end portion of the other housing.
A coil spring 16 is provided within the connector housing 23, and presses the splice member 4, received within this connector housing, against a positioning wall 17b on the front end portion of the front housing 17 to thereby fix this splice member.
As shown in FIGS. 41 and 42, the splice member 4 includes a base member 5, a cover member 6 superposed on this base member 5, and first and second clamp members 14 and 15 which grip and fixedly hold the superposed base member 5 and cover member 6 in intimate contact with each other.
An optical fiber holding groove 8 in which the above-mentioned first optical fiber 2 and second optical fiber 20 are inserted is formed in a surface of the base member 5 on which the cover member 6 is to be superposed. This optical fiber holding groove 8 is a groove having a V-shaped transverse cross-section, and a width, depth, etc., of this groove are so determined that the optical fibers, introduced into the groove, can be held between an inner surface of the groove and the surface of the cover member 6.
A ferrule holding portion 7 for supporting the outer periphery of the ferrule 3 introduced into the base member 5 from the front side is formed at the front end of the base member 5.
A procedure of assembling the mechanical splice-type connector 1 is as follows.
The ferrule 3 is beforehand inserted into the front housing 17.
Then, as shown in FIGS. 41 and 42, the ferrule 3 is introduced into the base member 5 in such a manner that the first optical fiber 2, projecting from the distal end of the ferrule 3, is located in a front half portion of the optical fiber holding groove 8, and thereafter the cover member 6 is superposed on the base member 5. Then, the base member 5 and the cover member 6 are fixed and held in intimate contact with each other by the first and second clamp members 14 and 15, thus completing the splice member 4.
Then, the coil spring 16 and the rear housing 18 are fitted on the rear end portion of the splice member 4, and the rear housing 18 and the front housing 17 are engaged with each other, and are fixed together, thus providing the completed form shown in FIGS. 40 and 43.
The connection of the second optical fiber 20 to the mechanical splice-type connector 1 is effected at an optical fiber installation field or the like, using a special-purpose optical fiber connection jig.
Wedge insertion slits 4a and 4b for forcing the intimately-contacted surfaces of the base member 5 and cover member 6 apart from each other against urging forces of the first and second clamp members 14 and 15 are formed in side surfaces of the base member 5 and cover member 6 of the splice member 4, and the connector housing 23 has openings 15a and 15b through which the wedge insertion slits 4a and 4b are exposed.
The special-purpose optical fiber connection jig has wedge pieces 21 which are fitted into the wedge insertions slits 4a and 4b in the splice member 4 to form a gap between the base member 5 and the cover member 6 intimately contacted with each other as shown in FIGS. 44(a) and 44(b) so that the second optical fiber 20 can be easily inserted into the optical fiber holding groove 8 of the splice member 4 (see, for example, Patent Literature 1, Patent Literature 2).
(Patent Literature 1)
JP-A-9-96735
(Patent Literature 2)
JP-A-2002-71999
In a condition in which a gap is formed between the base member 5 and the cover member 6 of the splice member 4 by the special-purpose optical fiber connection jig, the second optical fiber 20, made bare at the distal end portion of the coated optical fiber 19, is introduced into the optical fiber holding groove 8 from the rear side of the splice member 4, and the first optical fiber 2 and the second optical fiber 20 are butted in the optical fiber holding groove 8. Then, when the wedge pieces 21 are withdrawn respectively from the wedge insertion slits 4a and 4b, the first optical fiber 2 and the second optical fiber 20 are held between the base member 5 and the cover member 6, and are fixed thereto, with their end surfaces abutting against each other, so that the first optical fiber 2 and the second optical fiber 20 are connected together.
However, in the optical fiber connection jig of the above Patent Literature 1, the wedge pieces and a wedge drive mechanism for advancing and retracting the wedge pieces by operating a lever are provided on a table top-type base for supporting and fixing the splice member, and therefore this jig has a large size and an increased weight, and therefore it is difficult to carry the jig. And besides, this jig has a problem that it can not be easily operated with one hand at the field or the like, and the poor handleability at the field and a high cost of the jig have been a cause for a dull demand of the mechanical splice-type connector itself.
With respect to a problem common to Patent Literature 1 and Patent Literature 2, there is not provided any guide member for accurately positioning the center axis of the optical fiber in the center axis of the optical fiber holding groove in the splice member when inserting the optical fiber into the optical fiber holding groove, and the operator must manually align the center axes of the two with each other while confirming this operation with the eyes, and therefore there has been encountered a problem that the efficiency of the operation is poor.
Furthermore, when the inserting operation is carried out with the center axis of the optical fiber disposed out of alignment with the center axis of the optical fiber holding groove, there has been a fear that the distal end of the optical fiber strikes against an edge of an opening of the optical fiber holding groove, so that the fiber distal end is subjected to chipping or the like. When the fiber distal end is thus chipped, it is necessary to carry out a restoration operation in which the chipped fiber distal end portion is removed, and the optical fiber distal end is trimmed. This becomes a cause for further lowering the efficiency of the operation.
This invention has been made in view of the above problems, and its object is to provide an optical fiber connection jig which is small in size, lightweight and excellent in portability, and besides is simple in structure, and can be produced at a low cost, and enables an optical fiber to be easily and positively inserted into an optical fiber holding groove in a splice member without imposing any burden of alignment or others on the operator when inserting the optical fiber into the optical fiber holding groove, and achieves excellent handleablity at the field so that an increased demand for mechanical splice-type connectors can be expected.